--- a/jdk/src/java.httpclient/share/classes/java/net/http/SSLTunnelConnection.java	Wed Jun 15 10:25:25 2016 -0700
+++ b/jdk/src/java.httpclient/share/classes/java/net/http/SSLTunnelConnection.java	Wed Jun 15 19:18:19 2016 +0100
@@ -150,6 +150,10 @@
         // TODO: check for closure
         String s = "Receive) ";
         //debugPrint(s, r.buf);
+        if (r.result.bytesProduced() > 0) {
+            assert buf == r.buf;
+        }
+
         return r.result.bytesProduced();
     }